Mathematical Bold Small F 𝐟

Visual Description: A bold, stylized small f formed with thick strokes. The character sits on the baseline with a rounded loop and a concise tail. In math fonts it contrasts with regular weight letters, helping it stand out in formulas. It resembles a standard f but feels heavier and more formal.

Meaning & Usage: This symbol often represents a function or a variable. Used in formulas and annotations, the bold form signals emphasis or a distinct role. In calculators and editors, it helps separate a function name from regular text. It is common in UI labels for math features.

Historical Background: The Mathematical Bold set exists to give stylized variants for variables and operators. Designers use it to keep math distinct from prose. The idea grew from print traditions and later font standards. It encourages consistent emphasis across documents, software, and educational materials.

Practical Use: In teaching materials and apps, a bold f can mark a function key or a variable that needs focus. It fits formulas, graphs, and quick UI controls for operations or comparisons. Use it with calculators, math editors, or design tools to highlight function-related actions.

See our category page for related symbols.

Look‑alikes: f (U+66).

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